JP3637817B2 - Device connection method and program recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a device connection method for controlling a plurality of devices connected on a bus, and a program recording medium.
[0002]
[Prior art]
In recent years, in view of the spread of digital technology in digital video and communication satellite broadcasting, attempts have been made to connect and control digital devices using such digital technology on the same bus.
[0003]
In such a bus, the IEEE 1394 bus is capable of signal transmission between arbitrary devices in any connection form, can be hot-plugged / removed in a cable used for connection, and is real-time data such as an AV signal. (Isochronous data) and non-real-time data (asynchronous data) such as device control commands can be transmitted at the same time, so it has high compatibility with personal computers (PCs) and related devices, etc. For the reason, it is expected that it will be widely used in the future as a digital bus having excellent versatility.
[0004]
FIG. 7 is a diagram showing physical connections on the IEEE 1394 bus for explaining the present invention. As shown in the figure, each device such as camcorder 0 and VTR1 is connected to an IEEE 1394 bus having a plurality of channels, and constitutes one system that can be controlled as a unit.
[0005]
In the IEEE 1394 bus, AV signals of a plurality of channels can be input / output through one connector. That is, the number of connectors and the number of signal channels that can be handled are irrelevant. In addition, a single connector can input and output signals. A plug is defined as a virtual connector capable of inputting (outputting) one channel. There are two types of plugs, one for input and one for output, and one input (output) plug can input (output) one channel. Accordingly, a unit that can simultaneously input (output) n-channel isochronous packets has n input (output) plugs.
[0006]
For these plugs, a register (PCR: Plug control register) is defined for specifying a channel number to be handled and ON / OFF of operation. There are two types of PCR: input (iPCR) and output (oPCR). The contents are shown in FIG.
[0007]
Since the PCR is located in the address space of the IEEE1394 bus, it can be directly read out or the value can be changed using an Asynchronous packet. That is, no special control command is required to perform signal input / output control, and PCR can be realized by hardware.
[0008]
The Connection Management Procedure (CMP) is used to connect signals between units using this PCR. CMP provides three types of signal connection methods: 1) Broadcast out connection, 2) Broadcast in connection, and 3) Point-to-Point connection.
[0009]
FIG. 6 is a diagram for explaining conventional broadcast connection and point-to-point connection in the system configuration shown in FIG. A broadcast out connection is a connection between an output plug and one channel. In FIG. 6A, the camcorder has established a broadcast out connection to the channel 63. A Broadcast in connection is established between the channel 63 and the monitor 4. That is, the data output by the camcorder is input to the monitor 4 via a medium called a channel.
[0010]
Broadcast out connections can be disconnected by other units. For example, when the user presses the PLAY button on the VTR-2, the VTR-2 disconnects the broadcast out connection that the camcorder is making, and establishes the broadcast out connection between the channels 63 by itself. I can do it. In this case, since the monitor 4 continues the broadcast in connection of the channel 63, the displayed screen is automatically switched to the video from the VTR-2 (FIG. 6 (b)).
[0011]
When the VTR-2 disconnects the camcorder's Broadcast out connection, the SID field in the CIP header shown in the figure is used. The VTR-2 detects that another unit (camcorder) is outputting to the channel 63 to be output, and knows the node ID of the unit from the SID field. VTR-2 reads the oPCR of the transmitting unit using this node ID. Further, it learns that channel 63 is only used for the Broadcast out connection, and disconnects this connection by rewriting the value of oPCR.
[0012]
As a result, the camcorder stops outputting isochronous packets on the channel 63, so that the VTR-2 can establish a broadcast out connection between the channel 63 and itself. The SID is used not only when stopping broadcast out of other nodes, but also when the receiver establishes a point-to-point connection. For example, in FIG. 6A, when the VTR-2 inputs the channel 63 and starts recording the input signal, when executing an application such as establishing a point-to-point connection described later with the camcorder. But you can get the node ID of the sending unit from the SID.
[0013]
On the other hand, when it is desired to perform a protected signal connection between two specific units, a point-to-point connection is used. In FIG. 6, a channel 61 is used to establish a point-to-point connection from the STB to the VTR-1. A point-to-point connection is a one-to-one connection that can only be disconnected by the unit that established it. Point-to-point connections can be established not only by output units and input units, but also by third party units. For example, the editing controller can establish a point-to-point connection between the playback-side VTR and the recording-side VTR. In addition, by establishing a point-to-point connection between the STB output and the VTR-2, it is possible to perform one-to-two communication from the STB to the VTR-1 and VTR-2.
[0014]
What kind of connection is established in which case is a design matter of the device and is not defined by the AV protocol.
[0015]
The digital input / output plug and the external input / output plug can set broadcast connection from other units by the DIGITAL INPUT and DIGITAL OUTPUT control commands shown in FIG. On the other hand, the point-to-point connection is performed by directly rewriting the iPCR and oPCR values, and no control command for setting is prepared.
[0016]
[Problems to be solved by the invention]
As shown above, in the broadcast out connection, it is possible to disconnect by other units, so the unit that wants to output can disconnect the connection and output instead, but the point-to-point In connection, since only the unit that established it can be disconnected, there is a problem that transmission and reception of signals cannot be performed instead.
[0017]
Similarly, in a point-to-point connection, only the unit that established it can be disconnected, so when the sender or third party establishes a point-to-point connection, the signal received by the receiver is There is a problem that the connection cannot be disconnected even if it becomes unnecessary. In this case, in order to realize the disconnection when the receiving side becomes unnecessary, an operation such as inquiring from the transmitting side or a third party whether or not the receiving side is unnecessary is necessary. On the other hand, when the transmission side establishes a point-to-point connection, if it is no longer necessary for the transmission side to output a signal, the transmission side may disconnect the point-to-point connection.
[0018]
When the receiving side establishes the point-to-point connection, if the signal received by the receiving side becomes unnecessary, the receiving side may disconnect the point-to-point connection. At this time, if it is no longer necessary for the transmitting side to output a signal, the output signal becomes an invalid packet called an empty packet, which indicates that it is no longer necessary for the transmitting side to output a signal. The point-to-point connection can be disconnected without the inquiry operation by the side.
[0019]
In this way, it is desirable to establish a point-to-point connection from the receiving side, but it is not determined to be established from the receiving side by the standard, so it cannot be enforced. Further, there may be a case where it is desired to manage connections mainly by units other than the receiving side, such as management from a third party.
[0020]
The present invention has been made in view of such problems, and an object of the present invention is to provide a device control method and a program recording medium that can efficiently control connection of units connected on a bus.
[0021]
[Means for Solving the Problems]
In order to achieve the above object, the present invention according to claim 1 is characterized in that a unit having at least one of an input plug for inputting a signal and an output plug for outputting a signal is provided on an IEEE 1394 bus. at two connected becomes a system, a device connection method for connecting the unit, the predetermined first unit on the IEEE1394 bus is connected on the IEEE1394 bus is other than the first unit outputs a control command to the second unit asked to perform Point-to-Point connection, the second unit has a step of establishing the Point-to-Point connection receiving said control command a device connection method only the second unit establishing the Point-to-Point connection is characterized in that can cleave the Point-to-Point connection.
[0022]
The invention of claim 2 is the device connection method according to claim 1, wherein the control command is a target for performing point-to-point connection. It is the apparatus connection method characterized by having the information which specifies said 2nd unit.
[0023]
Further, the invention of claim 3 is the device connection method according to claim 1, wherein the second unit has received the control command, said first unit that outputs the control command Point- A device connection method characterized by establishing a To-Point connection.
[0024]
Further, the present invention of claim 4 is the device connection method according to claim 1, wherein the control command includes information for specifying a plug to be subjected to the point-to-point connection. This is a device connection method.
[0025]
Further, the invention of claim 5 is the device connection method according to claim 1, wherein the second unit has received the control command, a new Point-To-Point designated by the control command If you have already established a Point-to-Point connection to another party and the other party of the connection, the second unit is established already between said other party A device connection method comprising: disconnecting a point-to-point connection and establishing a point-to-point connection with the new destination.
[0026]
Further, the invention of claim 6 is the device connection method according to claim 1, the predetermined first unit on the IEEE1394 bus is connected on the IEEE1394 bus is other than the first unit and outputs a control command to the second unit is asked to perform a Point-to-Point connection, the second unit establishes the Point-to-Point connection receiving said control commands, the Point-the to A program recording medium recording a program for causing a computer to execute a step in which only the second unit that establishes a -Point connection can disconnect the Point-To-Point connection, and which can be processed by the computer It is.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0028]
(Embodiment)
FIG. 1 is a diagram for explaining a device connection method according to an embodiment of the present invention in the system configuration shown in FIG . In the following description of the embodiments, a control command is abbreviated as a command.
[0029]
As shown in FIG. 1, it is assumed that the VTR 1 has initially established a point-to-point connection with the STB 3. Since VTR1 is established, units other than VTR1 cannot disconnect this point-to-point connection. Here, if the controller 5 wants to dub from VTR2 to VTR1, the point-to-point connection established between VTR1 and STB3 is disconnected from VTR2 to VTR1, and newly between VTR2 and VTR1. A command for requesting establishment of a point-to-point connection, here, a command called an ESTABLISH P2P command is issued.
[0030]
If the VTR1 is recording the signal from STB3 and the point-to-point connection established between VTR1 and STB3 is being used effectively and you do not want to disconnect it, inform VTR2 and indicate that (REJECTED). When VTR1 does not record the signal from STB 3, if the point-to-point connection established between VTR1 and STB3 can be disconnected, the command is accepted and established between VTR1 and STB3. Disconnect the point-to-point connection and establish a new point-to-point connection between VTR2 and VTR1 (ACCEPT).
[0031]
Note that VTR1 initially established a point-to-point connection with STB3, but if there is no device that has established a point-to-point connection with VTR1 in advance, it receives a command. VTR1 attempts to establish a point-to-point connection with VTR2.
[0032]
In addition, establishment of a point-to-point connection may fail due to a lack of available bandwidth or channels necessary for connection.
[0033]
Next, consider the case where the above-mentioned Point-To-Point connection is temporarily established by a third party other words STB3, as before, cut Point-To-Point connection established between the VTR1 and STB3 and, the VTR2 is VTR 1, even as new issues a command for requesting to establish a Point-to-Point connection between VTR2 and VTR 1, VTR 1 is, Point was already established Tei a command from another -Since the To-Point connection cannot be disconnected, tell the VTR2 to that effect (REJECTED).
[0034]
In addition, although the example which the controller 5 sends a command to VTR1 was given, it is also possible for the VTR2 to send the command to the VTR1 by itself when the VTR2 wants to dubb the VTR1 from itself.
[0035]
FIG. 2 shows the contents of the ESTABLISH P2P command, which is an example of the present invention. The plug field specifies a plug that establishes a point-to-point connection. The level field indicates the level forcing the connection to be established for situations where the unit receiving the command has already received a signal. The contents of the level field are shown in FIG.
[0036]
The status field always has a value of FF (hexadecimal number) in the command. FIG. 5 shows the contents of the status field in the response to the command. The status field in the response indicates the content of the connection actually made or the reason why it was impossible for the condition indicated in the level field.
[0037]
The input_type field indicates that the isochronous channel number used for connection is designated or not designated, and is left to the unit that has received the command. The contents of the input_type field are shown in FIG.
[0038]
The connected node_ID field has information that identifies a unit to be connected, here a node ID value, and the unit that has received the command identifies the unit to be connected by this connected node_ID field.
[0039]
This field is not required if it is specified that a connection is established with the unit that sent the command.
[0040]
The connected plug_ID field has information for identifying the plug in the unit to be connected, here the plug number, and the unit that has received the command has the unit to be connected by this connected plug_ID field. Identify which of these plugs the connection is established with.
[0041]
By providing a new ESTABLISH P2P control command that requests the receiver to establish a point-to-point connection as described above, the receiver can always establish a connection even when the sender or a third party wants to establish a connection. Establish a method for establishing point-to-point connections. As a result, the connection can be disconnected when the receiving side becomes unnecessary. When the transmitting side becomes unnecessary, by continuing to transmit an Empty Packet, the receiving side knows that the transmission is invalid and disconnects the connection. As described above, a device connection method capable of efficiently controlling the connection of each unit connected on the bus is obtained.
[0042]
In this embodiment, by continuously sending an empty packet, the receiving side knows that it is an invalid transmission and disconnects, or the sending side informs that it wants to stop sending and receives the notification. The receiving side may disconnect the connection.
[0043]
In addition, it is possible to set an arbitrary unit connected to the IEEE 1394 bus regardless of a third party unit such as a controller.
[0044]
In any of the embodiments of the present invention, the apparatus connection method of the present invention has been mainly described. However, as a recording medium of the present invention, all or a part of the functions of the respective means described above, or each step. A recording medium that stores a program that causes a computer to execute all or a part of the above may be used.
[0045]
【The invention's effect】
As is apparent from the above description, according to the present invention, the transmission side or a third party can connect by newly providing a control command for requesting the reception side to establish a point-to-point connection. The receiver can always establish a point-to-point connection even when it is desired to establish a connection. As described above, there is an effect that an apparatus connection method and a program recording medium capable of efficiently controlling the connection of each unit connected on the bus are obtained.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a device connection method according to an embodiment of the present invention. FIG. 2 is a diagram showing contents of an ESTABLISH P2P command. FIG. 3 is a diagram showing contents of a level field. Figure showing contents [Figure 5] Figure showing contents of status field in response to ESTABLISH P2P command [Figure 6] Figure for explaining conventional broadcast connection and point-to-point connection [Figure 7] Fig. 8 shows the physical connection of units for explanation. Fig. 8 shows the configuration of DIGITAL INPUT and DIGITAL OUTPUT commands related to conventional connections. Fig. 9 shows the configuration of iPCR and oPCR. Fig. 10 Isochronous transmission. Showing the structure of the CIP header in AV data transmission using the [Description of symbols]
0 Camcorder 1 VTR1
2 VTR2
3 STB
4 Monitor 5 Controller

Claims (6)

Device connection for connecting the units in a system in which at least two units having at least one of an input plug for inputting a signal and an output plug for outputting a signal are connected on the IEEE 1394 bus A method,
The predetermined first unit on IEEE1394 bus, ask the so connected on the IEEE1394 bus and outputs a control command to the second unit is other than the first unit performing the Point-To-Point connection And
The second unit comprises receiving the control command and establishing the point-to-point connection ;
Device connection method characterized in that only the second units established the Point-To-Point connection can cut the Point-To-Point connection. The apparatus connection method according to claim 1, wherein the control command includes information for specifying the second unit to be a point-to-point connection target. A device connection method according to claim 1, characterized in that the second unit has received the control command establishes output by the first unit and the Point-To-Point connecting said control command Device connection method. 2. The apparatus connection method according to claim 1, wherein the control command includes information for specifying a plug to be subjected to the point-to-point connection. A device connection method according to claim 1, wherein the second unit has received the control command, another party from the other party of the designated new Point-To-Point connection by the control command If you already have established a Point-to-Point connection, the second unit by cutting the Point-to-Point connections established already between said other party against To establish a point-to-point connection with the new destination. 2. The device connection method according to claim 1 , wherein a predetermined first unit on the IEEE 1394 bus outputs a control command to a second unit connected to the IEEE 1394 bus and other than the first unit. asked to perform Point-to-Point connection, the second unit establishes the Point-to-Point connection receiving said control commands, the second establishing the Point-to-Point connection A program recording medium recording a program for causing a computer to execute a step capable of disconnecting the point-to-point connection only by a unit , and which can be processed by the computer .

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